Heat-relaxable substrates and arrays

ABSTRACT

Articles, such as high density arrays, on heat-relaxable substrates that can be relaxed by exposure to thermal energy are disclosed, along with methods of manufacturing the arrays, and systems/apparatus for relaxing arrays using electromagnetic energy. The arrays may themselves include electromagnetic energy sensitive material in their construction, in which case exposure of the arrays to suitable electromagnetic energy can provide the thermal energy required to cause the arrays to relax. In other embodiments, the arrays may not include an electromagnetic energy sensitive material in their construction, in which case the arrays may be heated indirectly, i.e., by locating the arrays within a system or apparatus that includes an electromagnetic energy sensitive material and transferring the thermal energy from the electromagnetic energy sensitive material to the array by, e.g., conduction.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a division of co-pending U.S. patentapplication Ser. No. 09/708,916, filed Nov. 8, 2000, which is acontinuation of U.S. patent application Ser. No. 09/459,418, filed Dec.9, 1999, now abandoned.

FIELD OF THE INVENTION

[0002] The present invention relates to heat-relaxable substrates. Moreparticularly, the present invention provides high density arrays onheat-relaxable substrates, along with methods and apparatus for relaxingsubstrates using electromagnetic energy.

BACKGROUND

[0003] Arrays may be used in a variety of applications, such as genesequencing, monitoring gene expression, gene mapping, bacterialidentification, drug discovery, and combinatorial chemistry. Many ofthese applications involve expensive and oftentimes difficult to obtainsamples and reagents. Accordingly, high density arrays are desirablebecause the use of such arrays may dramatically increase efficiency withrespect to limited or expensive samples when compared to standardarrays, such as a 96 well plate. For example, a 96 well plate mayrequire several hundred microliters of sample per well to run adiagnostic experiment whereas a high-density array would require only afraction of that sample for the entire array. In addition to thereduction of volume, miniaturization allows hundreds or thousands oftests to be performed simultaneously. Furthermore, a high-density arraymay be more versatile than a standard array because of the widevariation of chemistries that may be present on a single array.

[0004] Problems in the manufacturing of high-density arrays on standardsubstrates, e.g., glass microscope slides, include the need for multiplesteps to produce the arrays with densely packed reactants. Themanufacture of high-density arrays is further complicated when differentchemistries are required at different binding sites on the arrays, suchas required for manufacturing nucleic acid arrays.

[0005] Attempts to address the need for high-density arrays haveincluded using oriented polymeric films in place of glass slides as thesubstrate for the arrays. The arrays can include binding sites formed onthe oriented polymeric films in a larger format that is easier tomanufacture, after which the oriented polymeric films can be relaxed byapplying thermal energy to the substrate to provide arrays withhigh-density binding sites. Examples of such arrays are described in WO99/53319 (HIGH DENSITY, MINIATURIZED ARRAYS AND METHODS OF MANUFACTURINGSAME, published Oct. 21, 1999) and commonly assigned U.S. patentapplication Ser. No. 09/287,379, filed Apr. 7, 1999, entitled HIGHDENSITY, MINIATURIZED ARRAYS AND METHODS OF MANUFACTURING SAME.

[0006] Although the oriented polymeric films provide significantadvantages in array manufacturing, their use does pose additionalproblems during the substrate relaxation process. One potential problemis achieving uniform transmission of thermal energy to the arraysubstrate. Another potential problem is curling or other distortion ofthe substrate during the application of thermal energy to inducerelaxation.

[0007] Oriented polymeric films used in, e.g., packaging applications,are typically relaxed using thermal energy supplied by air. When used aspackaging, however, the flatness of the film after relaxation istypically not important because the film is constrained around apackage, typically conforming to the shape of the package. Inapplications where a flat film is desired after relaxation, the film istypically placed in tension. An example of one such application is inthe use of oriented polymeric films over windows to prevent drafts,provide additional insulation, etc. When used on windows, the film isheld in tension between, e.g., adhesive tapes applied to the windowframe. When provided as the substrate of an array, however, the film isnot so constrained or tensioned, thereby causing the potential forcurling as described above.

[0008] Another issue to address is how to quickly and efficiently supplythe thermal energy required to relax the film. The use of conductiveheating devices, e.g., hot plates, may require the constant attention ofan operator or feedback control systems to prevent overheating and/oruneven heating of the film.

[0009] Another concern with heat-relaxable arrays manufactured withattached or embedded materials that make the array useful forbioanalytical applications, e.g., DNA, RNA, proteins, polysaccharides,antibodies, etc., is that the application of excessive thermal or otherforms of energy may adversely affect the functional performance of thematerials on the array.

SUMMARY OF THE INVENTION

[0010] In some embodiments, the present invention provides articlescomprising polymeric heat-relaxable substrates suitable for use inmanufacturing arrays, wherein the substrates include electromagneticenergy sensitive material for use in relaxing the substrates uponexposure to electromagnetic energy. In other embodiments, the presentinvention provides articles, such as high density arrays, includingheat-relaxable substrates that can be relaxed by exposure toelectromagnetic energy. Methods of relaxing arrays includingheat-relaxable substrates and reactants affixed thereto are alsoprovided in connection with the present invention. In still otherembodiments, the present invention also provides methods ofmanufacturing such articles, as well as systems and apparatus forrelaxing the same using electromagnetic energy.

[0011] In some embodiments, the substrates suitable for use inmanufacturing arrays may themselves include electromagnetic energysensitive Curie point material in their construction, in which caseexposure of the substrates to suitable electromagnetic energy canprovide the thermal energy required to cause the substrates to relax.The substrates may additionally comprise linking agents or masks, inwhich case the electromagnetic energy sensitive material may be includedin the linking agents or masks. Such methods for providing energy may bereferred to as direct heating, i.e., no additional apparatus must besupplied to cause the conversion of electromagnetic energy to heat thatis used to relax the substrates.

[0012] In preferred embodiments, the substrates include a coating oflinking agents, with electromagnetic sensitive material included in thesubstrate. In a most preferred embodiment, arrays include reactantsaffixed to the substrates.

[0013] Substrates that include an electromagnetic energy sensitivematerial in their construction may also be placed in a system orapparatus that also includes the same or a different electromagneticenergy sensitive material to provide the thermal energy needed to relaxthe substrate when exposed to electromagnetic energy.

[0014] In its various aspects, the present invention provides aconvenient manner of relaxing substrates that include heat-relaxablematerial. The amount of energy supplied to relax the substrates can beeasily controlled and the process can be performed quickly andeconomically.

[0015] In preferred embodiments, wherein reactants are affixed to thesubstrates, additional benefits may be achieved. For example, afterrelaxation, the resulting high density arrays can provide a level offlatness useful in achieving accurate hybridization results.

[0016] In another aspect of the invention, methods are provided forrelaxing a substrate. In one embodiment, a method includes providing anarray including a heat-relaxable substrate and reactants affixedthereto; providing electromagnetic energy sensitive material inproximity to the substrate; and directing electromagnetic energy towardsthe electromagnetic energy sensitive material, wherein theelectromagnetic energy is converted into thermal energy and conducted tothe heat-relaxable material, thereby causing the heat-relaxable materialin the substrate to relax.

[0017] In another aspect, the present invention provides apparatus forrelaxing heat-relaxable articles. In one aspect, the present inventionincludes the apparatus having a first surface; a second surface opposedto and spaced from the first surface; and electromagnetic energysensitive material in thermal communication with the first surface,whereby heating of the electromagnetic energy sensitive material byelectromagnetic energy increases the temperature of the first surface.

[0018] These and other features and advantages of the present inventionare described in connection with illustrative embodiments of theinvention below.

GLOSSARY

[0019] For purposes of this invention, the following definitions shallhave the meanings set forth.

[0020] “Affix” shall include any mode of attaching reactants to asubstrate. Such modes shall include, without limitation, covalent andionic bonding, adherence, such as with an adhesive, and physicalentrapment within a substrate. In the case of linking agents, reactantsmay be affixed to the substrate by linking agents that are created byfunctionalizing a surface, such as with an acid wash, or by linkingagents that are coated on the substrate.

[0021] “Analyte” shall mean a molecule, compound, composition orcomplex, either naturally occurring or synthesized, to be detected ormeasured in or separated from a sample of interest. Analytes include,without limitation, proteins, peptides, amino acids, fatty acids,nucleic acids, carbohydrates, hormones, steroids, lipids, vitamins,bacteria, viruses, pharmaceuticals, and metabolites.

[0022] “Binding site” shall mean a discrete location on a substratewherein reactants are affixed thereto. A single binding site may includea quantity of one or more of the same reactants affixed to thesubstrate.

[0023] “Curie point material” shall mean a magnetic material having aCurie temperature sufficiently high to raise a “Heat-relaxable” materialto or above its relaxation temperature when exposed to electromagneticenergy

[0024] “Electromagnetic energy” shall mean energy having rapidlyoscillating electric and magnetic components, regardless of wavelengthor frequency, that can provide the energy required to relax an array,e.g., microwave energy and radio-frequency (RF) energy.

[0025] “Heat-relaxable” shall mean, in the context of a material, suchas a substrate, that the material undergoes some relaxation in at leastone dimension in response to the transmission of thermal energy into thematerial.

[0026] “Linking agent” shall mean any chemical species capable ofaffixing a “Reactant” to the substrate.

[0027] “Microwave energy” shall mean electromagnetic energy having afrequency in the range of from about 10⁸ Hz to about 3×10¹¹ Hz.

[0028] “Radio Frequency (RF) energy” shall mean electromagnetic energyhaving a frequency in the range of from about 10⁴ Hz to about 10⁷ Hz.

[0029] “Reactant” shall mean any chemical molecule, compound,composition or complex, either naturally occurring or synthesized, thatis capable of binding an analyte in a sample of interest either alone orin conjunction with a molecule or compound that assists in binding theanalyte to the substrate, such as, for example, a coenzyme. Thereactants of the present invention are useful for chemical orbiochemical measurement, detection or separation. Accordingly, the term“Reactant” specifically excludes molecules, compounds, compositions orcomplexes, such as ink, that do not bind analytes as described above.Examples of reactants include, without limitation, amino acids, nucleicacids, including oligonucleotides and cDNA, carbohydrates, and proteinssuch as enzymes and antibodies.

[0030] “Relaxation temperature” shall mean the temperature at which aheat-relaxable material exhibits a desired amount of relaxation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031]FIG. 1 is a cross-sectional view of a portion of one arrayaccording to the present invention.

[0032]FIG. 2 is a plan view of the array of FIG. 1 before relaxation.

[0033]FIG. 3 is a plan view of the array of FIG. 2 after relaxation.

[0034] FIGS. 4-9 are cross-sectional views of alternative articlesaccording to the present invention.

[0035]FIG. 10 is a schematic diagram of one system and apparatus forrelaxing an article formed on a heat-relaxable substrate.

[0036]FIG. 11 is a schematic diagram of another system and apparatus forrelaxing an article formed on a heat-relaxable substrate.

[0037]FIG. 12 is a schematic diagram of another system and apparatus forrelaxing an article formed on a heat-relaxable substrate.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS OF THE INVENTION

[0038] The present invention provides articles including heat-relaxablesubstrates suitable for use in, e.g., manufacturing arrays. The presentinvention also provides high density arrays on heat-relaxablesubstrates, along with methods and apparatus for relaxing substratesusing electromagnetic energy. The methods include methods ofmanufacturing arrays and methods of relaxing the substrates usingelectromagnetic energy. The apparatus are useful in combination with thearrays to provide high-density arrays that are generally flat.

[0039] With reference to FIGS. 1-3, an array 10 is illustrated andincludes a heat-relaxable substrate 20, a layer 30 includingelectromagnetic energy sensitive material on the substrate 20, and alinking agent coating 40 on the layer 30. The substrate 20 is preferablyprovided as a film with a thickness of, e.g., about 0.005 millimeters(mm) to about 0.05 mm.

[0040] The substrate 20 is preferably constructed of a heat-relaxablematerial such as an oriented polymer. It may be preferred that thesubstrate 20 consist essentially of heat-relaxable material, althoughsome fillers and other inactive materials may be included. It ispreferred, however, that the heat-relaxable material cause substantiallythe entire substrate 20 to relax upon the application of thermal energy.That relaxation is preferably, but not necessarily, generally uniform inthe in-plane directions (see, e.g., the “x” and “y” directions in FIG.2) over the major surfaces of the substrate 20 .

[0041] Although the heat-relaxable material is described herein ascausing the substrate 20 to relax, it should be understood that therelaxation is primarily in the size of the major surfaces of thesubstrate 20 . The thickness of the substrate 20 may, however, actuallyincrease as a result of the relaxation.

[0042] Some preferred oriented polymers that can be used as theheat-relaxable material in the substrates 20 of the present inventioninclude biaxially oriented low-density polyethylenes; biaxially orientedlinear low-density polyethylenes; and biaxially oriented ultralow-density polyethylenes. Biaxially oriented substrates are preferredbecause they exhibit relaxation in two orthogonal in-plane directions(see, e.g., the “x” and “y” directions in FIG. 2). Other orientedsubstrates that may be suitable for use in the present invention includeuniaxially, biaxially, or multiaxially oriented substrates made by anyprocess known to the art, including but not limited to melt-orientation;the blown film, bubble, double-bubble, and tubular processes; lengthorientation; the process of tentering; extension over a mandrel;thermoforming; and blow molding.

[0043] Polymers which may be employed in substrates of the inventioninclude, but are not limited to, polyethylenes, including high densitypolyethylene, low density polyethylene, linear low density polyethylene,ultra low density polyethylene, and copolymers of ethylene (includingethylene propylene copolymers and ethylene vinyl acetate copolymers);polyolefins, including isotactic polypropylene, syndiotacticpolypropylene, and polymethylpentene; polyacetals; polyamides, includingpolyamide 6 and polyamide 66; polyesters, including polyethyleneterephthalate, polybutylene terephthalate, and polyethylene naphthalate;halogenated polymers, including polyvinyl chloride, polyvinylidenechloride, polychlorotrifluoroethylene, polyvinyl fluoride, andpolyvinylidene fluoride; styrene polymers, including general purposepolystyrene and syndiotactic polystyrene; cellulose esters, includingcellulose acetate and cellulose propionate; polyketones, includingpolyetheretherketone and copolymers and terpolymers of carbon monoxidewith ethylene and/or propylene; polycarbonates, including thepolycarbonate of bisphenol A; phenyl-ring polymers, includingpolyphenylene sulfide; polysulfones; polyurethanes; polymers of acrylicand methacrylic acids and their esters; ionomers; and copolymers,blends, or layered structures of any of the above-named polymers.Oriented substrates of any of these polymers may be optionallycross-linked.

[0044] Regardless of its composition, the oriented polymer substrate 20can be relaxed by the application of thermal energy after it has beenmanufactured. The amount of relaxation observed in the substrate 20depends at least partially on the degree to which the substrate 20 wasoriented during manufacturing. The relaxation need not be equal in anytwo orthogonal directions within the plane of the substrate 20, althoughsubstantially uniform relaxation in the two orthogonal directions ispreferred. In considering relaxation as a function of direction in thesubstrate plane, substantial uniformity of directionally-dependentrelaxation from point to point within the substrate 20 is preferred;that is, the substrate preferably relaxes in substantially the sameamount in each direction, regardless of position on the substrate. Ifthe substrate 20 does not exhibit substantially uniform relaxationcharacteristics, a registration indicator system may be added to thebinding sites 44 or otherwise employed to register the binding sites inthe finished array.

[0045] While the starting materials for the substrate 20 are preferablyoriented polymers, the oriented polymers in the array substrates 20 arepreferably no longer oriented and, in fact, may be isotropic afterrelaxation.

[0046] The layer 30 including electromagnetic energy sensitive materialthat is provided on the substrate 20 can take a variety of forms.Examples of some suitable materials may include those described in U.S.Pat. Nos. 5,278,377 (Tsai); 5,446,270 (Chamberlain et al.); 5,529,708(Palmgren et al.); and 5,925,455 (Bruzzone et al.).

[0047] Although the layer 30 is depicted as being in direct contact withthe substrate 20, one or more intervening layers may be located betweenthe layer 30 and substrate 20 provided that the electromagnetic energysensitive material in the layer 30 is in thermal communication with theheat-relaxable material in the substrate 20 such that thermal energy inlayer 30 is conducted to the substrate 20.

[0048] Regardless of its specific form, however, the electromagneticenergy sensitive material in the layer 30 absorbs electromagnetic energyand converts the incident electromagnetic energy into heat such that thethermal energy of the electromagnetic energy sensitive materialincreases. That thermal energy is then transmitted to the heat relaxablematerial of the substrate 20 (typically through conduction). The thermalenergy raises the temperature of the heat-relaxable material in thesubstrate. The amount of relaxation is dependent upon the heat-relaxablematerial in the substrate 20, the temperature to which theheat-relaxable material is heated, and whether the substrate 20 isconstrained during heating and/or subsequent cooling.

[0049] The heat-relaxable material is preferably raised to at least itsrelaxation temperature. As defined above, the relaxation temperature isthe temperature at which a desired amount of relaxation, e.g., asdescribed in WO 99/53319, is obtained.

[0050] Where the electromagnetic energy is to be provided in the form ofmicrowave energy, any one or more of three phenomena may result in theconversion of the microwave energy to thermal energy. Those phenomenainclude dielectric heating due to electric dipole interaction with theelectric field component of the incident microwave energy. Anotherphenomenon that may be involved in the energy conversion is resistiveheating, in which the oscillating electric field component of theincident microwave energy interacts with conduction band electrons inthe material. Yet another phenomenon that may be experienced is magneticheating, in which magnetic dipole interaction of the material with theoscillating magnetic field component of the incident microwave energyheats the material.

[0051] One characterization of an electromagnetic energy sensitivematerial used in connection with the present invention can be based onthe dielectric loss factor of the electromagnetic energy sensitivematerial. In general, the relative dielectric loss factor of a materialindicates the ability of the material to generate thermal energy viafriction in an oscillating electromagnetic (microwave) field. For mostarrays of the present invention, the materials used for the substrate20, e.g., oriented polymers, do not, alone, show any appreciablerelaxation when exposed to electromagnetic radiation such as microwavesor RF energy.

[0052] For example, the electromagnetic energy sensitive material willtypically possess a relative dielectric loss factor that is greater thanthe relative dielectric loss factor of the heat-relaxable material ofthe substrate 20. In such a configuration, the thermal energy of theelectromagnetic energy sensitive material will increase more rapidlythan the thermal energy of the heat-relaxable material when subjected tomicrowave energy (understanding that the thermal energy of theheat-relaxable material and other constituents in the substrate 20 maynot increase at all upon exposure to microwave energy). As the thermalenergy of the electromagnetic energy sensitive material increases, atleast a portion of the thermal energy is transmitted to other materialsin the contact with the electromagnetic energy sensitive material.

[0053] As illustrated in FIG. 1, electromagnetic energy sensitivematerial can be provided as a part of the array 10 in the form of acoating or layer 30, substantially all of which is an electromagneticenergy sensitive material. In other words, the layer 30 may consistessentially of an electromagnetic energy sensitive material. Forexample, the layer 30 may be metallic, e.g., it includes one or moremetals, one or more metallic compounds, or combinations of one or moremetals and one or more metallic compounds. The metals or metalliccompounds of layer 30 are preferably of the type that absorbelectromagnetic energy and convert that energy into thermal energy.

[0054] Where layer 30 is metallic, the composition and/or thickness ofthe layer may be selected, at least in part, on the frequency ofelectromagnetic energy to be used to heat the substrate 20. Wheremicrowave energy is to be used, it may be preferred that the metalliclayer be relatively thin. If the metallic layer is too thick, it maycrack and cause arcing during heating of the substrate 20 or it mightnot heat sufficiently to relax the substrate. Another consideration inselecting the thickness of a metallic layer 30 is that a layer that istoo thick may constrain the substrate 20 from relaxing in response tothe application of thermal energy.

[0055] In some embodiments where layer 30 is metallic and microwaveenergy is to be used as the energy source, it may be preferred that thelayer 30 be, e.g., about 100 Angstroms thick or less. Another manner inwhich to characterize the thickness of the layer 30 is by the opticaldensity of the layer, typically measured before the arrays are relaxed.For example, it may be preferred that the optical density of the layer30 on the substrate 20 be about 0.5 or less before relaxation,optionally even more preferably about 0.3 or less.

[0056] If the thermal energy is to be supplied to the array 10 in theform of RF energy and the layer 30 is metallic, it may be thicker thanif microwave energy was to be used to heat the substrate 20. The upperlimit of any metallic layer to be used for RF induction will typicallybe controlled by the propensity of thicker metallic layers to prevent orconstrain the array from relaxing in response to heating.

[0057] One potential advantage of array 10 is that if the layer 30includes one or more metals, one or more metallic compounds, orcombinations of one or more metals and one or more metallic compounds,then layer 30 may also function as a mask layer to reduce backgroundfluorescence from the substrate 20. Such mask layers are discussed incopending, commonly-assigned U.S. patent application Ser. No.09/410,863, filed on Oct. 1, 1999, entitled ARRAYS WITH MASK LAYERS ANDMETHODS OF MANUFACTURING THE SAME.

[0058] Although illustrated as a generally continuous layer 30 on thesubstrate 20, it should be understood that the thickness of the layer 30may vary to provide improved control over the amount of electromagneticenergy converted to thermal energy ( and, thus, available for transferto the substrate 20). Another alternative for controlling the conversionprocess includes providing layer 30 in a discontinuous pattern on thesubstrate 20. In some instances, it may be desirable to provide bothvariations in thickness and a discontinuous pattern to improve controlover the relaxation process.

[0059] As illustrated in FIG. 1, the array 10 may also include a coating40 that includes linking agents. The linking agents in coating 40 areselected based on the reactants 42 to be affixed to the array 10 and theapplication for which the array 10 will be used. It is preferred, butnot required, that the linking agent coating 40 be applied oversubstantially all of the surface of the substrate 20. One example of asuitable linking agent useful in many different arrays is an azlactonemoiety.

[0060] Reactants 42 can be affixed to the array 10 to create bindingsites 44 as depicted in FIGS. 1-3, where FIG. 2 is top plan view of thefront side of the array 10 before relaxation and FIG. 3 is a top planview of the array 10 after relaxation. As described in, e.g., WO99/53319 (HIGH DENSITY, MINIATURIZED ARRAYS AND METHODS OF MANUFACTURINGSAME, published Oct. 21, 1999), any number of processes known in the artmay be used to introduce the reactants 42 to be affixed to the linkingagent coating 40. The mode of affixation may vary in accordance with thereactant or reactants employed.

[0061] The type of reactant 42 used in the present invention will varyaccording to the application and the analyte of interest. For example,when characterizing DNA, oligonucleotides may be preferred. Whenconducting diagnostic tests to determine the presence of an antigen,antibodies may be preferred. In other applications, enzymes may bepreferred. Accordingly, suitable reactants include, without limitation,amino acids, nucleic acids, including oligonucleotides and cDNA,carbohydrates, and proteins such as enzymes and antibodies.

[0062] With reference to FIGS. 2 and 3, in one embodiment, a variety ofnucleic acids, such as oligonucleotides can be affixed at separatebinding sites 44. The variety of oligonucleotides at the differentbinding sites 44 permits a large number of potential binding eventsbetween reactants and target analytes in a sample.

[0063] The reactants 42 may be affixed to the binding sites 44 prior to,during or after relaxation of the underlying substrate 20. However, itis preferred to affix the reactants 42 prior to relaxing the substrate20 to take advantage of the methods of the present invention forproviding high-density arrays including high reactant binding sitedensities.

[0064] The array 10 of FIGS. 1-3 illustrates only one construction ofarrays that are relaxable using electromagnetic energy. FIG. 4illustrates another article 110 that includes a substrate 120 similar tothe substrate 20 of array 10 described above. The article 110 alsoincludes an optional linking agent coating 140. A difference in theconstruction of article 110 from array 10 illustrated in FIG. 1 is thatthe layer 130 including the electromagnetic energy sensitive material islocated on the opposite of the substrate 120 from the linking agentcoating 140.

[0065]FIG. 5 illustrates another construction in which the article 210includes a substrate 220 including heat-relaxable material and a linkingagent coating 240. In between these two layers are a layer 230 includingparticles 232 of electromagnetic energy sensitive material located in amatrix. The thermal energy induced in the layer 230 by the particles 232of electromagnetic energy sensitive material is preferably transmittedto the underlying substrate 220.

[0066]FIG. 6 illustrates yet another embodiment of an article 310designed to relax in response to exposure to electromagnetic energy. Thearticle 310 includes a substrate 320 of a heat-relaxable material and alinking agent coating 340. The electromagnetic energy sensitive materialin layer 330 in this embodiment may preferably be a Curie point material(one example of which is discussed in U.S. Pat. No. 5,278,377).

[0067] It is generally preferred that the Curie point material possess aCurie temperature that is at least about as high as the relaxationtemperature of the heat-relaxable material. To prevent or reduce thechance of overheating the article 310, it may be preferred that theCurie temperature be no greater than about 10° C. above the relaxationtemperature, more preferably no greater than about 20° C. above therelaxation temperature.

[0068] Depending on the properties of the heat-relaxable material, itmay be preferred that the Curie temperature of the Curie point materialbe at least as high as the glass transition temperature (T_(g)) of theheat-relaxable material used in the substrate 320. It may further bepreferred that the Curie temperature be at least about 10° C. above theT_(g) of the of the heat-relaxable material in the substrate 320. Toprevent or reduce the chance of overheating the article 310, it mayoptionally be preferred that the Curie temperature be no greater thanabout 20° C. above the T_(g) of the heat-relaxable material in thesubstrate 320.

[0069] Alternatively, some heat-relaxable materials that may be used insubstrates of the present invention may exhibit relaxation as theheat-relaxable material passes through its crystalline melt transition.For those materials, it may be preferred that the Curie temperature beat least as high as the crystalline melt temperature (T_(m)) of theheat-relaxable material used in the substrate 320. To prevent or reducethe chance of overheating the article 310, it may optionally bepreferred that the Curie temperature be no greater than about 10° C.,more preferably no greater than about 20° C., above the T_(m) of theheat-relaxable material in the substrate 320.

[0070] In another manner of characterizing the Curie point materialsused in connection with the present invention, it may be preferred thatthe Curie temperature of the materials be about 175° C. or less,alternatively about 165° C. or less, and, in yet another alternative,about 155° C. or less.

[0071] Curie point materials react to the magnetic component ofmicrowave energy and convert the absorbed energy to thermal energy at arelatively high rate until the material reaches a particular temperature(the Curie point). Once the Curie point temperature is reached, the rateat which the Curie point materials react to the magnetic component ofthe electromagnetic energy is reduced, which limits the temperature towhich the materials are heated. Further control over the heating may beobtained by locating an electrically conductive ground plane inproximity to the Curie point material to eliminate heating of the Curiepoint material due to the electric field component of the incidentenergy, and thereby enhancing heating of the magnetic field component.

[0072] Although layer 330 is illustrated as being a single, homogeneouslayer, the Curie point material may be provided in particulate oranother dispersed form within a matrix. For example, the Curie pointmaterial may be held within a polymeric matrix, with the matrix and theCurie point material together making up the layer 330.

[0073]FIG. 7 illustrates a variation from the article 310 of FIG. 6. Thearticle 410 of FIG. 7 includes a substrate 420 and a linking agentcoating 440. Also in the article 410 is a layer 430 including anelectromagnetic energy sensitive material, preferably a Curie pointmaterial. The difference in the article 410 from the article 310 is thatthe linking agent coating 440 is separated from the layer 430 includingthe electromagnetic energy sensitive material by the substrate 420. Thisseparation may help to further insulate or protect the linking agentcoating 440 from the effects of excessive thermal energy from the layer430.

[0074]FIG. 8 illustrates yet another embodiment of the invention inwhich an article 510 is provided that includes a substrate 520 and alinking agent coating 540. Particles 530 of an electromagnetic energysensitive material are located within the substrate 520 whicheffectively functions as a matrix for the particles 530. Electromagneticenergy absorbed by the particles 530 of electromagnetic energy sensitivematerial and converted to thermal energy can be conductively transmittedto the heat-relaxable material of the substrate 520 surrounding each ofthe particles 530.

[0075]FIG. 9 illustrates another embodiment of an article 610 includinga substrate 620 and a linking agent coating 640. The electromagneticenergy sensitive material in the article 610 is provided as particles630 dispersed in the linking agent coating 640.

[0076]FIG. 10 illustrates one embodiment of a system 80 for usingelectromagnetic energy to relax a substrate including heat-relaxablematerial while reducing or eliminating curling or other distortionsduring relaxation. The system 80 is designed for use with articles thatinclude electromagnetic energy sensitive material as described in any ofthe embodiments described above in connection with FIGS. 1-9. In otherwords, the system 80 is useful in the direct heating method usingarticles that include an electromagnetic energy sensitive material intheir construction.

[0077] The apparatus used in the system 80 includes a pair of opposinggenerally planar surfaces 50 and 60 that face each other and are spacedapart from each other, between which the article, such as a substrate orarray, 10 is located. By locating the article 10 between the surfaces 50and 60, curling or other deformation of the article 10 caused byrelaxation can be reduced or eliminated. It is preferred that spacing sbetween the surfaces 50 and 60 be slightly larger than the thickness ofthe article 10 after relaxation to reduce the likelihood that thearticle 10 is constrained from relaxing due to frictional forces betweenthe article 10 and the surface 50 and 60. In some aspects, it may bepreferred that the spacing be about 4 millimeters (mm) or less, morepreferably about 3 mm or less, and even more preferably about 2 mm orless. It may also preferred that any components between the source ofelectromagnetic energy 70, e.g., a microwave generator, and the article10 be substantially transparent to the electromagnetic energy.

[0078] To facilitate its use with articles including Curie pointmaterials as the electromagnetic energy sensitive material, the system80 may optionally include an electrically conductive ground plane inproximity to at least one of the surfaces 50 and 60. In the illustratedembodiment, a ground plane 52 is located beneath surface 50. Asdiscussed above, the ground plane may be useful to reduce or preventheating of the articles by electric field effects and to enhance heatingby magnetic field effects.

[0079]FIG. 11 illustrates another system 180 that may be used inconnection with the direct heating method, i.e., for heating articlesthat include an electromagnetic energy sensitive material in theirconstruction. In addition, the system 180 itself includes anelectromagnetic energy sensitive material and, thus, may also be used inthe indirect heating method, i.e., for heating arrays that do notinclude an electromagnetic energy sensitive material in theirconstruction, e.g., arrays described in WO 99/53319 (HIGH DENSITY,MINIATURIZED ARRAYS AND METHODS OF MANUFACTURING SAME, published Oct.21, 1999).

[0080] The system 180 may include an electromagnetic source 170 (e.g., amicrowave generator) as well as an apparatus having two opposinggenerally flat surfaces 150 and 160 that face each other and are spacedapart from each other, between which an article 710 (including forillustration purposes substrate 720 and linking agent coating 740) canbe located. By placing the article 710 between the surfaces 150 and 160,curling or other deformation of the article 710 caused by relaxing canbe reduced or eliminated.

[0081] It is preferred that the spacing between the surfaces 150 and 160be slightly larger than the thickness of the article 710 afterrelaxation to reduce the likelihood that the article 710 is constrainedfrom relaxing due to frictional forces between the article 710 and thesurfaces 150 and 160. In some aspects, it may be preferred that thespacing be about 4 millimeters (mm) or less, more preferably about 3 mmor less, and even more preferably about 2 mm or less. That spacingbetween surfaces 150 and 160 may be accomplished by any suitablemechanism such as, e.g., shims 152 and 154 as illustrated in FIG. 11. Itis preferred that the spacing between the surfaces 150 and 160 beadjustable such that, after the article 710 is relaxed, the spacingbetween surfaces 150 and 160 can be reduced to compress the article 710while it is still warm, thereby potentially further improving itsflatness. That adjustable spacing may be accomplished by, e.g., removingthe shims 152 and 154 from the apparatus such that the upper surface 160lays on the article 710.

[0082] Because the article 710 may not itself include anyelectromagnetic energy sensitive material, or at least anyelectromagnetic energy sensitive material in sufficient amounts toprovide the thermal energy required to relax the substrate 720 of thearticle 710, the apparatus used to support the article 710 duringrelaxation preferably includes electromagnetic energy sensitivematerial. In the illustrated apparatus, the lower surface 150 includes alayer 730 that preferably includes electromagnetic energy sensitivematerial. The layer 730 may consist essentially of electromagneticenergy sensitive material, or it may include electromagnetic energysensitive material in, e.g., particulate form as described above inconnection with some of the articles. Regardless of the actual form inwhich the electromagnetic energy sensitive material is provided,however, the layer 730 preferably contains electromagnetic energysensitive material in sufficient amounts to convert enoughelectromagnetic energy to thermal energy that can be used to relax thearticle 710.

[0083] Also illustrated in FIG. 11 is an optional electricallyconductive ground plane 736 located underneath the layer 730 includingelectromagnetic energy sensitive material. If the electromagnetic energysensitive material used in layer 730 is a Curie point material, theground plane 736 can reduce or prevent heating via electric fieldeffects while enhancing the heating via magnetic field effects.

[0084] Furthermore, although the system 180 is discussed as being usefulfor articles that do not themselves contain any electromagnetic energysensitive material, it should be understood that articles that doinclude an electromagnetic energy sensitive material as discussed abovewith respect to, e.g., FIGS. 1-9, may be used in connection with thesystem 180.

[0085]FIG. 12 illustrates another apparatus useful in, e.g., the system180 that includes two opposing generally planar surfaces 850 and 860,between which an article 810 (such as a substrate or array) can belocated. By placing the article 810 between the surfaces 850 and 860,curling or other distortion of the article 810 occurring duringrelaxation can be reduced or eliminated. It is preferred that thespacing between the surfaces 850 and 860 be slightly larger than thethickness of the article 810 after relaxation to reduce the likelihoodthat the article 810 is constrained from relaxing due to frictionalforces between the article 810 and the surfaces 850 and 860.

[0086] To further reduce any frictional forces that may constrainrelaxation of the article 810, the surface 850 and 860 preferablyinclude layers 852 and 862 of, respectively, a low surface energymaterial, e.g., polytetrafluoroethylene (PTFE) or similar materials,that reduce sticking to the surfaces 850 and 860. Another differencebetween the apparatus of FIGS. 11 and 12 is that the apparatus of FIG.12 includes two layers 830 a and 830 b that each include electromagneticenergy sensitive material, with layer 830 a located below the array 810and layer 830 b located above the article 810.

Test Methods

[0087] Optical Density

[0088] The optical densities described herein were determined using aMacbeth TD931 Densitometer Instrument (Macbeth Process Measurements,Division of Kollmorgen Corporation, New York, U.S.A.). This instrumenthas an orthochromatic filter and measures optical density (OD) readingsfrom 0 to 4.0 (±0.02). The instrument was calibrated before use with astandard at 3.04 OD.

[0089] Test Method X

[0090] A square substrate of about 75 millimeters (mm) by about 75 mmwas placed inside the center of a microwave oven (Sharp Microwave Oven,Model R-510 BK, 1100 watts power) and the sample was subjected tomicrowave radiation at full power for the time indicated in Table 1.After that period, the heated substrate was removed from the oven,placed on a smooth flat surface, and flattened by placing a glassmicroscope slide on the top surface of the film until cooled.

[0091] Test Method Y

[0092] A square substrate of about 75 mm by about 75 mm was placed in adevice similar to that illustrated in FIG. 11. The upper surface wasformed by a ceramic block (McMaster Carr Supply Company, Chicago, Ill.,U.S.A., 150 mm square by 13 mm thick). The lower surface was formed by apad of Curie point material as described below located in a depressionformed in a second ceramic block, the depression having the samedimensions as the pad. The dimensions of the pad were about 125 mm×90mm, with a thickness of about 0.75 mm. A ground plane was not includedin the device. Shims were used to space the upper surface about 3 mmfrom the lower surface (such that the flat sample substrate was not incontact with the upper surface). The device, with the sample locatedtherein, was subjected to microwave radiation (using the same oven as inMethod X at full power) for the time indicated in Table 1.

[0093] After sample was heated by microwave energy for the indicatedperiod of time, the shims spacing the upper surface from the lowersurface were removed such that the upper surface was allowed to makecontact with the relaxed sample. The flat, relaxed sample was removedand the Curie point pad in the device was allowed to cool until itreached 50±3° C. At this point, the next sample was placed on the padand the above relaxation process was repeated for all samples.

[0094] The pad of Curie point material was made in the following manner:a mixture of 15.4 g of Dow Corning Sylgard 182 Silicone (14.0 g siliconeelastomer plus 1.4 g crosslinker) and 23.9 ml of metal powder (74.6g)was prepared by hand mixing with a spatula. The metal powder was anamorphous alloy with the composition (atom %) of 69% iron, 8% chromium,15% phosphorus, 5% carbon and 3% boron, with a particle size under 35microns. The metal powder had a Curie onset temperature of 151° C. Theuncured silicone/metal mixture was placed in a sandwich construction(top to bottom): precision surfaced aluminum plate (6 mm thick)/unprimedpolyethylene terephthalate film (0.05 mm)/silicone-metal surrounded by0.75 mm thick spacers/unprimed polyethylene terephthalate film (0.05mm)/precision surfaced aluminum plate (6 mm thick). This stack of layerswas pressed flat for 10-15 minutes. The silicone material with the metalpowder contained therein was then cured by placing the stack of layersin a 90° C. oven for 12 hours.

EXAMPLES

[0095] The following examples merely serve to further illustratefeatures, advantages, and other details of the invention. It is to beexpressly understood, however, that while the examples serve thesepurposes, the particular ingredients and amounts used as well as otherconditions and details are not to be construed in a manner that wouldunduly limit the scope of this invention.

[0096] All of the examples involved sample substrates that were formedfrom oriented polyethylene film (Cryovac D955) from Sealed AirCorporation (Simpsonville, S.C., U.S.A.).

[0097] The examples indicate that the oriented polyethylene film itselfexhibits no discernible relaxation in response to exposure to microwaveenergy, but that heating of an electromagnetic energy sensitive materialthat can conduct thermal energy to the heat-relaxable material in thesubstrates can be effective in relaxing the substrates without adverselyaffecting the hybridization properties of the arrays. TABLE 1 OpticalMethod X Method X Method Y Method Y Example Density (seconds) Result(seconds) Result 1 0 600 no relaxation 90 relaxation 2 0 600 norelaxation 60 relaxation 3 0 600 no relaxation 40 relaxation 4 0.11 70relaxation 40 relaxation 5 0.10 70 relaxation 40 relaxation 6 0.19 10relaxation 10 relaxation 7 0.15 10 relaxation 10 relaxation 8 0.54 10relaxation  5 relaxation 9 0.26 15 relaxation 10 relaxation 10 0.26 2arcing  5 relaxation 11 0.15 60 constrained 60 constrained relaxationrelaxation 12 0.33 10 relaxation 10 relaxation 13 0.15 10 relaxation 10relaxation 14 0.13 15 relaxation 15 relaxation 15 0.18 10 relaxation 10relaxation 16 0.13 15 relaxation 15 relaxation

Example 1

[0098] A 0.025 mm thick oriented polyethylene film was coated with a0.75% azlactone copolymer solution (70:30 percent ratio ofN,N-dimethylacrylide/vinyl dimethyl azlactone copolymers) in IPA thatwas crosslinked with 10% EDA using a standard extrusion coating method.This coated substrate was further coated with a 0.3% solution of LinearPEI in IPA. There was no discernible relaxation after 10 minutes ofexposure to microwave radiation during Method X testing. Using Method Y,the sample substrate was relaxed, i.e., for purposes of these examples,all discernible relaxation had ceased, although some distortions in theshape of the relaxed substrates was observed. It is theorized that thesedistortions may have been caused by the array sticking to the Curiepoint material pad during extended processing times. These distortionsmay be less frequent in substrates that include a metal coating on thesubstrate.

Example 2

[0099] A 0.025 mm thick oriented polyethylene film was printed with apattern of circular spots according to the method described in Example 1of WO 99/53319 (HIGH DENSITY, MINIATURIZED ARRAYS AND METHODS OFMANUFACTURING SAME, published Oct. 21, 1999).

[0100] The sample substrate exhibited no visible relaxation after 10minutes of exposure to microwave radiation during Method X testing.Using Method Y, the sample substrate was relaxed, although somedistortions in the shape of the relaxed substrates was observed. It istheorized that these distortions may have been caused by the arraysticking to the Curie point material pad during extended processingtimes. These distortions may be less frequent in substrates that includea metal coating on the substrate.

Example 3

[0101] A 0.015 mm thick oriented polyethylene film was supplied with apattern of spots as in Example 2. The sample substrate exhibited novisible relaxation after 10 minutes of exposure to microwave radiationduring Method X testing. Using Method Y, the sample substrate wasrelaxed, although some distortions in the shape of the relaxedsubstrates was observed. It is theorized that these distortions may havebeen caused by the array sticking to the Curie point material pad duringextended processing times. These distortions may be less frequent insubstrates that include a metal coating on the substrate.

Examples 4 and 5

[0102] A 0.025 mm thick oriented polyethylene film was coated with alayer of titanium using standard sputtering methods with a web coatermanufactured by Mill Lane Engineering (Lowell, Mass., U.S.A.). Thesample substrates were heated by Method X and Method Y as indicated inTable 1 to relax the substrate until no further relaxation was observed.

Examples 6-8

[0103] A 0.025 mm thick oriented polyethylene film was coated with alayer of titanium using standard sputtering methods with a web coatermanufactured by Mill Lane Engineering (Lowell, Mass., U.S.A.). Samplesubstrates were heated by Method X and Method Y as indicated in Table 1until no further relaxation was observed.

[0104] After relaxation by Method Y, striations from excessive heatingwere observed in the relaxed sample substrate of Example 8.

Example 9

[0105] A 0.025 mm thick oriented polyethylene film was plasma treated inan oxygen environment followed by coating with chromium (Cr) using avapor deposition method in which the metal is vaporized by electron beamevaporation out of a graphite crucible insert made by Denton Vacuum(Moorestown, N.J., U.S.A.). The chromium coated sample substrates weretested using both Methods X and Y and full relaxation occurred in bothtests.

Example 10

[0106] A 0.025 mm thick oriented polyethylene film was plasma treated inan oxygen environment followed by coating with gold (Au) using a vapordeposition method in which the metal is vaporized by electron beamevaporation out of a graphite crucible insert made by Denton Vacuum(Moorestown, N.J., U.S.A.). The microwave energy was discontinued after2 seconds during Method X testing due to visible arcing of the samplesubstrate. After relaxation by Method Y, striations from excessiveheating were observed in the relaxed sample substrate. It is believedthat arcing could be prevented or reduced by providing a thinner coatingof Au.

Example 11

[0107] A 0.025 mm thick oriented polyethylene film was plasma treated inan oxygen environment followed by coating with tin (Sn) using a vapordeposition method in which the metal is vaporized by electron beamevaporation out of a graphite crucible insert made by Denton Vacuum(Moorestown, N.J., U.S.A.). It appears that both samples wereconstrained from further relaxation due to the physical nature of the Sncoating.

Example 12

[0108] A 0.025 mm thick oriented polyethylene film was coated with alayer of titanium, followed by coating of the titanium layer with a0.75% azlactone copolymer solution (70:30 percent ratio ofN,N-dimethylacrylide/vinyl dimethyl azlactone copolymers) in isopropylalcohol (IPA) (2-Propanol, Aldrich, Milwaukee, Wis., U.S.A.) that wascrosslinked with 10% ethylenediamine (EDA, Aldrich) using a standardextrusion coating method. This coated substrate was further coated witha 0.03% solution of polyethyleneimine (Linear PEI, Aldrich) in IPA. Thesample was then relaxed by both Methods X and Y.

Example 13

[0109] A 0.025 mm thick oriented polyethylene film was coated with alayer of titanium, followed by coating of the titanium layer with a0.75% azlactone copolymer solution (70:30 percent ratio ofN,N-dimethylacrylide/vinyl dimethyl azlactone copolymers) in IPA thatwas crosslinked with 10% EDA using a standard extrusion coating method.This coated substrate was further coated with a 0.3% solution of LinearPEI in IPA. The sample was then relaxed by both Methods X and Y.

Example 14

[0110] A 0.015 mm thick oriented polyethylene film was coated with alayer of titanium, followed by coating of the titanium layer with a0.75% azlactone copolymer solution (70:30 percent ratio ofN,N-dimethylacrylide/vinyl dimethyl azlactone copolymers) in IPA thatwas crosslinked with 10% EDA using a standard extrusion coating method.This coated substrate was further coated with a 0.3% solution of LinearPEI in IPA. The sample was then relaxed by both Methods X and Y.

Examples 15 and 16

[0111] A 0.015 mm thick oriented polyethylene film was coated withtitanium by standard sputtering methods using a web coater manufacturedby Mill Lane Engineering (Lowell, Mass., U.S.A.). Sample substrates wereheated by Method X and Method Y as indicated in Table 1 until no furtherrelaxation was observed.

Example 17

[0112] This example serves to demonstrate that DNA can be adsorbed ontothe coated substrate and subjected to microwave energy without adverselyaffecting hybridization of the DNA to a complementary sequence.

[0113] Arrays on oriented polyethylene film substrates preparedaccording to Example 12 were tested according to the following protocol.Arrays on standard non-shrinking positively charged nylon substrates 40mm×80 mm, 0.165 mm thick (Schleicher and Schuell, BR0812, BioRoboticsInc., Woburn, Mass., U.S.A.) were also prepared as controls.

[0114] Samples of Pasteurella Multocida DNA (Gen Bank Accession No.E05329) were prepared with sterile DNase and RNase free water (CatalogNo. 10977-015, Life Technologies, Baltimore, Mass., U.S.A.) using thefollowing primer sets: forward primer, AGAGTTTGATCATGGCTCAG (SEQ ID NO:1), [Bases 09-28] and reverse primer, AGCAGCCGCGGTAATACG (SEQ ID NO: 2),[Bases 523-540]. The samples had the following compositions:Undiluted—25 nanograms per microliter (ng/μl); 1:10-2.5 ng/μl; 1:50-0.5ng/μl; 1:100-0.25 ng/μl; and 1:1000-0.025 ng/μl.

[0115] Six microliters (μl) of denatured alcohol and 9 μl of a solutionincluding 5× sodium chloride sodium citrate (SSC) (Catalog No.15557-044, Life Technologies, Baltimore, Mass., U.S.A.) and 0.2% sodiumdodecyl sulfate solution (SDS) (Catalog No. 15553-035 Life Technologies,Baltimore, Mass., U.S.A.) were added to each dilute DNA sample and anegative control sample.

[0116] The diluted DNA samples prepared as described above were heatedfor 10 minutes at 100° C. and immediately placed on ice. After spinning,2 μl of each diluted DNA sample was spotted onto each of the orientedpolyethylene substrates and the nylon controls in a known pattern. Thenylon control substrates were rinsed with 2× ssc prior to spotting. Allof the spotted arrays were allowed to air dry.

[0117] A first set of three spotted oriented polyethylene filmsubstrates were then heated according to Method Y described above.Substrate one was heated for seven seconds. Substrate two was heated forten seconds. Substrate three was heated for twelve seconds. Afterstopping the microwave oven after heating each substrate, the shims wereremoved from the apparatus and then the entire device was removed fromthe oven. The top plate of the device was removed and the substrate wasallowed to cool for about 30 seconds before removing it from the pad ofCurie point material. Before each heating cycle, the entire device wascooled to 50±3° C.

[0118] A second set of three oriented polyethylene film substrates werespotted and then heated according to Method Y as described above for tenseconds, thirteen seconds, and fifteen seconds, respectively. Beforeeach heating cycle, the device was cooled to 25±3° C.

[0119] The cooled, relaxed films and the nylon substrates were thenwrapped in SARAN WRAP™ and placed on a transilluminator (Eagle-Eye II,Stratagene, San Diego, Calif., U.S.A.) for 5 minutes.

[0120] After the arrays were completed, they were tested to determinewhether exposure to the microwave energy and/or heat during relaxationaffected the ability of the arrays on the film substrates to hybridizeas compared to the arrays on the nylon substrates. As part of thatprocess, a ³³P labeled primer kit (Catalog No. 300385, Stratagene, CedarCreek, Tex., U.S.A.) was used to label a complementary sequence to thespotted DNA. The complementary sequence was removed from a −80° C.freezer, thawed on ice and denatured at 100° C. for 10 minutes, afterwhich it was placed on ice.

[0121] One nylon substrate array was placed in a 50 milliliter (ml)Falcon tube and two oriented polyethylene substrate arrays were placedin a 50 ml Falcon tube. A Stratagene QuikHyb Buffer (Catalog No. 201220,Stratagene, Cedar Creek, Tex., U.S.A.) was gently inverted to mix thebuffer and 5 ml of the buffer was added to each Falcon tube. The Falcontubes were then placed into glass hybridization tubes which, in turn,were placed in a hybridization oven and mixed for 30 minutes at 68° C.After the initial 30 minute period, 100 μl of the labeled complementaryDNA was added to each Falcon tube and the tubes were returned to thehybridization oven for an additional 3 hours 68° C.

[0122] After removing the Falcon tubes from the oven, they were decantedand the arrays were placed in covered washing dishes. A washing solutionof 200 ml of 6× SSC and 0.1% SDS was added to each washing dish. Thecover was replaced on each of the washing dishes, which were placed on ashaker (LaPine Shaker, Fisher Scientific, Wood Dale, Ill. U.S.A.) andagitated at medium speed and mixed for 10 minutes. The original washsolutions were then decanted from the washing dishes and an additional200 ml of the washing solution was added to each of the washing dishesand agitated on the shaker at medium speed and mixed for an additional10 minutes, followed by decanting of the wash solutions.

[0123] Each of the washed arrays were sealed in heat-sealed bags andthen placed onto a Phosphorlmager cassette. The cassette was closed andthe radioactive signals from the arrays were allowed to transferovernight. The results were then analyzed using the Molecular DynamicsPhosphorimager (Molecular Dynamics Phosphorimager, Model SF, Sunnyvale,Calif., U.S.A.) and ImageQuant software.

[0124] No appreciable difference was observed in the signal intensity ofthe arrays on the nylon substrates versus the arrays formed on theoriented polyethylene film substrates. As desired, detectable signalswere obtained (under the exposure conditions) from the first fourdilutions used in preparation of the arrays. Had significant degradationof the DNA occurred during the microwave heating of the orientedpolyethylene film substrates, these lower dilutions would not beexpected to be observed. The results indicated that microwave heatinghad no appreciable effect on hybridization of the arrays.

[0125] The preceding specific embodiments are illustrative of thepractice of the invention. This invention may be suitably practiced inthe absence of any element or item not specifically described in thisdocument. The complete disclosures of all patents, patent applications,publications, and amino acid and nucleotide sequence databank deposits(as referenced herein by their accession number) cited herein areincorporated into this document by reference as if individuallyincorporated in total.

[0126] Various modifications and alterations of this invention willbecome apparent to those skilled in the art without departing from thescope of this invention, and it should be understood that this inventionis not to be unduly limited to illustrative embodiments set forthherein, but is to be controlled by the limitations set forth in theclaims and any equivalents to those limitations.

What is claimed is:
 1. A method of relaxing an array, comprising:providing an array comprising a heat-relaxable substrate and reactantsaffixed thereto; providing electromagnetic energy sensitive material inthermal communication with the substrate; directing electromagneticenergy towards the electromagnetic energy sensitive material, whereinthe electromagnetic energy is converted into thermal energy andconducted to the heat-relaxable material, thereby causing theheat-relaxable material in the substrate to relax.
 2. The method ofclaim 1, wherein the array further comprises linking agents.
 3. Themethod of claim 2, wherein the linking agents are included in a linkingagent coating on the substrate.
 4. The method of claim 2, wherein thelinking agents comprise an azlactone moiety.
 5. The method of claim 2,wherein the reactants are affixed to the linking agents at the pluralityof binding sites.
 6. The method of claim 1, wherein the reactants areselected from the group consisting of nucleic acids, proteins, andcarbohydrates.
 7. The method of claim 1, wherein the reactants compriseoligonucleotides.
 8. The method of claim 1, wherein the reactantscomprise cDNA.
 9. The method of claim 1, wherein the electromagneticenergy sensitive material comprises a Curie point material.
 10. Themethod of claim 9, wherein the heat-relaxable material of the substratehas a relaxation temperature, and further wherein the Curie pointmaterial has a Curie temperature of at least about the relaxationtemperature.
 11. The method of claim 9, further comprising providing anelectrically conductive ground plane in proximity with the Curie pointmaterial.
 12. The method of claim 1, further comprising contacting theheat-relaxable material with the electromagnetic energy sensitivematerial.
 13. The method of claim 12, further comprising removing thearray from contact with the electromagnetic energy sensitive materialafter directing electromagnetic energy towards the electromagneticenergy sensitive material.
 14. The method of claim 1, wherein theelectromagnetic energy sensitive material is on the substrate.
 15. Themethod of claim 14, wherein the electromagnetic energy sensitivematerial comprises a layer comprising one or more metals, one or moremetallic compounds, or combinations of one or more metals and one ormore metallic compounds.
 16. The method of claim 14, wherein thesubstrate comprises first and second major surfaces, and further whereinthe electromagnetic energy sensitive material contacts substantially allof at least one of the first and second major surfaces.
 17. The methodof claim 1, wherein the substrate comprises a coating includingparticulates of the electromagnetic energy sensitive material.
 18. Themethod of claim 17, wherein the coating further comprises linkingagents.
 19. The method of claim 1, wherein the energy-sensitive materialis provided in particulate form, and further wherein the electromagneticenergy-sensitive material particulates are located within theheat-relaxable material of the substrate.
 20. A heat-relaxable arraycomprising: a substrate comprising heat-relaxable material; reactantsaffixed to the substrate; and electromagnetic energy sensitive materialcomprising Curie point material in thermal communication with theheat-relaxable material.
 21. The array of claim 20, wherein theelectromagnetic energy sensitive material is in contact with thesubstrate.
 22. The array of claim 20, wherein the electromagnetic energysensitive material is on the substrate.
 23. The array of claim 22,wherein the substrate comprises first and second major surfaces, andfurther wherein the electromagnetic energy sensitive material contactssubstantially all of at least one of the first and second majorsurfaces.
 24. The array of claim 20, further comprising a coating oflinking agents on the substrate.
 25. The array of claim 24, wherein theCurie point material is located within the linking agent coating. 26.The array of claim 20, wherein the electromagnetic energy sensitivematerial is provided in particulate form, and further whereinelectromagnetic energy sensitive material is located within theheat-relaxable material of the substrate.
 27. An apparatus for relaxinga heat-relaxable substrate, the apparatus comprising: a first surface; asecond surface opposed to and spaced from the first surface; andelectromagnetic energy sensitive material in thermal communication withthe first surface, whereby heating of the electromagnetic energysensitive material by electromagnetic energy increases the temperatureof the first surface.
 28. The apparatus of claim 27, wherein the firstsurface comprises the electromagnetic energy sensitive material.
 29. Theapparatus of claim 27, wherein the electromagnetic energy sensitivematerial is provided in particulate form, and further wherein the firstsurface comprises particles of the electromagnetic energy sensitivematerial.
 30. The apparatus of claim 27, wherein the first and secondsurfaces comprise the electromagnetic energy sensitive material.
 31. Theapparatus of claim 30, wherein the electromagnetic energy sensitivematerial is provided in particulate form, and further wherein the secondsurface comprises particles of the electromagnetic energy sensitivematerial.
 32. The apparatus of claim 27, wherein the electromagneticenergy sensitive material comprises Curie point material.
 33. Theapparatus of claim 32, further comprising an electrically conductiveground plane proximate the electromagnetic energy sensitive material.34. The apparatus of claim 27, further comprising a spacing mechanismspacing the first surface from the second surface.
 35. The apparatus ofclaim 34, wherein the spacing mechanism comprises an adjustable spacingmechanism, wherein spacing between the first and second surfaces can beadjusted.
 36. The apparatus of claim 34, wherein the spacing mechanismcomprises at least one shim.
 37. The apparatus of claim 27, wherein thefirst and second surfaces comprise a low surface energy material.
 38. Anarticle for use in manufacturing an array, the article comprising: asubstrate comprising heat-relaxable material; and electromagnetic energysensitive material comprising Curie point material in thermalcommunication with the heat-relaxable material.
 39. The article of claim38 further comprising linking agents.
 40. The article of claim 39further comprising reactants affixed to said substrate.
 41. The articleof claim 38, wherein the electromagnetic energy sensitive material is incontact with the substrate.
 42. The article of claim 38, wherein theelectromagnetic energy sensitive material is on the substrate.
 43. Thearticle of claim 38, wherein the substrate comprises first and secondmajor surfaces, and further wherein the electromagnetic energy sensitivematerial contacts substantially all of at least one of the first andsecond major surfaces.
 44. The article of claim 39 wherein said linkingagents are coated on said substrate.
 45. The article of claim 44,wherein the Curie point material is located within the linking agentcoating.
 46. The article of claim 38, wherein the electromagnetic energysensitive material is provided in particulate form, and further whereinelectromagnetic energy sensitive material is located within theheat-relaxable material of the substrate.